Extreme cold and windchill warnings for most of Minnesota were canceled at midday Thursday by the National Weather Service, although much of the state is expected to endure high temperatures below zero through the afternoon, preceding a gradual warmup into the weekend.

Though it won't stick around long, the cold's arrival Wednesday had an impact, driving temperatures well below what had been forecast, forcing some school districts to postpone start times Thursday morning. It even cost the Twin Cities an expected record.

The temperature dropped to minus 11 Wednesday morning in the Twin Cities, well below the minus 5 that had been forecast Tuesday night. Typically, northwest winds carry air heated by the Twin Cities toward Minneapolis-St. Paul International Airport, keeping the official temperatures there relatively warm, noted National Weather Service forecaster Tony Zaleski. But Wednesday night the cold and extremely strong winds overwhelmed that effect.

"It was like a dam that broke," he said.

The deepest cold also arrived a few hours earlier than expected. Forecasts had indicated that the Twin Cities would not experience its first subzero reading of the winter until Thursday morning, but when it fell to minus 1 just before midnight, the date for the latest arrival of a subzero temperature in the Twin Cities remained Jan. 18.

Zaleski said he was glad the record wasn't broken.

"In this part of the country, it's supposed to be cold in winter," he said. "On top of that, there were so many records (for warmth) broken earlier this month."

The urban heat island was apparent on weather maps Thursday morning as the metro area and neighboring counties were surrounded by an extreme cold warning north, west and south, and a wind chill advisory to the southeast. An extreme cold warning is a recent addition to the list of warnings from the National Weather Service, and indicates dangerously low temperatures independent of wind chill.

The predicted high of 2 above in the Twin Cities Thursday would be the coldest high since Jan. 2, 2010, when the mercury topped out at 1 above. Gradual warming toward 30 is expected through the weekend, however, with some light snow predicted for the Twin Cities Thursday night and Friday.

Across much of the rest, of the state, however, the temperature will remain below zero Thursday and drop to teens below zero Thursday night.

The cold and wind warnings, meanwhile, activated an online survey of public responses to winter weather alerts, under an ongoing project by the weather service and St. Cloud State University. The survey is available at www.startribune.com/a958